ELECTROMAGNETIC ENERGY FLOW PATTERN ON THE AXIS OF A CIRCULAR DISK BY TRANSIENT EXCITATION
瞬态激励下圆盘轴向电磁能量的流动规律

The exact energy flow pattern on the axis of a circular disk by transient excitation is presented. It is shown that non-decaying region does not appear when the source is chosen to be a rectangular pulse, on the contrary, there exists a uprising region on the axis when the width of the pulse is less than a/c. After reaching its maximum value, the energy decays slowly until the law of r-2 is met. The scale of the uprising region is dependent upon the size of the antenna and the width of the pulse. The energy flow line tube excited by a harmonic wave is also given. It is also shown that there is a oscillatory region near the source, the amplitude is also uprising, which is quite different compared with the conclusion drawn by S. Silver (1949). Finally, the phenomenon of energy uprising in time domain is explained and some problems about the electromagnetic missiles are also expounded.